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Abstract: Triglavska Bistrica is a typical Alpine river in the north-western part of Slovenia. Its recharge area includes some of the highest peaks in the Julian Alps. The hydrogeological conditions and flow of the river depend largely on groundwater exchange between the karstified aquifer in the carbonate rocks and the intergranular aquifer in the glaciofluvial deposits. The average volume of the river flow is up to several m3/s. In this study, water samples from different locations along the river were analysed for stable isotope ratios of oxygen and hydrogen, major ions, and concentration of tritium activity. The correlation of major ions suggests that the recharge area consists of both limestone and dolomite rocks. The δ18O and δ2H values decrease downstream, implying that the average recharge elevation increases. At the downstream sampling site V-5, located approx. 300 m upstream from the confluence of the Sava Dolinka River, the calculated mean recharge altitude is estimated to be 1,996 m.
Keywords: groundwater, oxygen and hydrogen isotopes, hydrogeochemistry, recharge area, Alpine aquifer, Slovenia
Published in DiRROS: 09.03.2022; Views: 736; Downloads: 243
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Abstract: The European spruce bark beetle (Ips typographus L.) is an eruptive forest pest that has caused a great deal of damage in the last decades because of increasing climatic extremes. In order to effectively manage outbreaks of this pest, it is important to predict where they will occur in the future. In this study we developed a predictive model of the sanitary felling of Norway spruce (Picea abies (L.) H. Karst.) because of bark beetles. We used a time series of sanitary felling because of bark beetles from 1996 to 2020 in Slovenia. For the explanatory variables, we used soil, site, climate, geographic, and tree damage data from the previous year. The model showed that sanitary felling is negatively correlated with slope, soil depth, soil cation exchange capacity, and Standard Precipitation Index (less sanitary felling in wet years). On the other hand, soil base saturation percentage, temperature, sanitary felling because of bark beetles from the previous year, sanitary felling because of other abiotic factors from the previous year, and the amount of spruce were positively correlated with the sanitary felling of Norway spruce due to bark beetles. The model had an R2 of 0.38. A prediction was performed for 2021 combining an occurrence model and a quantitative model. The model can be used to predict the amount of sanitary felling of Norway spruce due to bark beetles and to refine the risk map for the next year, which can be used for forest management planning and economic loss predictions.
Keywords: sanitary felling, prediction, Ips typographus, Picea abies, Slovenia, forecasting, insect outbreak forest pest
Published in DiRROS: 21.02.2022; Views: 477; Downloads: 418
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Keywords: migration, school system, educational system, schools, migrant learners, surveys, interviews, participant observation, Slovenia
Published in DiRROS: 18.01.2022; Views: 625; Downloads: 205
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Abstract: It is expected that climate change as well as abiotic and anthropogenic disturbances will strongly influence temperate forests. Besides changes in the main climate variables, various disturbance factors may significantly worsen conditions for mesic Slovenian forests (SE Europe) dominated by European beech (Fagus sylvatica), Norway spruce (Picea abies) and European silver fir (Abies alba). In Slovenia, the climate has warmed in recent decades, with an average annual rate of increase of about 0.4°C per decade or even more than 0.5°C per decade in summer. In addition, disturbances have caused considerable damage to trees in the most extensive forest types in Slovenia, starting with a widespread ice storm in 2014, followed by bark beetle outbreaks, windthrows and salvage logging interventions. After 2014, salvage logging increased from about one third to two thirds of the total annual felling. Over the last two decades, we have observed a decline in Norway spruce growing stock, with the highest rate of decrease in areas below 500 m a.s.l., and an increasing trend for European beech. Overall, the three dominant species (beech, spruce, silver fir), which together account for more than 70% of the total growing stock, have shown a declining trend over the last 20 years. The patterns observed are broadly consistent with earlier predictions developed for different climate change scenarios and with those reported in many other European countries. Adaptive forest management, which implements close-to-nature silviculture, has been traditionally practised in the region under study and has the potential to play an important role in reducing the risks associated with the impacts of climate change and disturbances in the future.
Keywords: climate warming, disturbance factors, ice storm, bark beetle outbreaks, spruce decline, salvage logging, tree species composition, temperate forest, Slovenia
Published in DiRROS: 03.01.2022; Views: 601; Downloads: 532
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Keywords: migration, school system, educational system, schools, migrant learners, integration, Slovenia
Published in DiRROS: 10.05.2021; Views: 780; Downloads: 359
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